Cables, such as telecommunication cables, may carry hundreds and sometimes thousands of pairs of insulated wires, enclosed within flexible shields or tubular sheaths. When two or more cable ends are joined together, as for example when extending a cable or when tapping into an extended cable, a splice or splice area is created. Generally, the splice area should be enclosed, for protection from the environment. For example, if the closure is an aerial closure, used with aerially suspended cables, protection against damaging interference from weather elements, animals, plants and so forth may be necessary or desired. If the enclosure is a buried enclosure, protection against ground water, burrowing animals, and soil interference is generally required.
Structures adapted for enclosing such portions of cables are frequently referred to as "splice closures". Such closures are typically adapted to enclose therein at least two, and sometimes more "cable ends". The term "cable end" and variants thereof, as used herein, refers to an area of exposure of insulated conductors, i.e., wires and any additional wrappings or coverings involved.
Splice closures, or cable closures, generally comprise an elongate, typically cylindrical, casing having first and second opposite ends. Cables to be joined at the splice area are generally directed into the casing through the casing ends. At each of the casing ends, seal means are generally required in order to ensure an environmental seal around the cables, i.e. between the cables and the cable enclosure.
Generally, a plurality of features are desirable in any preferred seal system or arrangement for use in association with cable closure ends. First, generally the seal system should be such that it can be readily mounted around, or removed from association with, a continuous cable system. That is, the cable cannot generally be threaded through a single aperture, rather the seal arrangement should be adapted for mounting about an already positioned cable or cable splice.
Secondly, preferably the seal system is appropriate for accommodating a variety of sizes of cables, so that it can be conveniently applied in the field. Also, it should, preferably, be capable of adjustment for various directions of extension of associated cables, for example non-coaxial, and/or non-parallel, cables extending into a cable splice. A related problem concerns movement of the cable closure, for example under high winds or the like. Again, it is preferred that the seal system be such as to accommodate such movement without substantial loss of the protective seal(s).
It is also preferred that the seal system be replaceable as necessary, for example to accommodate new cables, new cable sizes, or merely to ensure a good environmental seal over a long period of time.
Other desirable features and seal systems for cable splice enclosures concern features facilitating easy and convenient assembly, since often assembly is done in the field. Field assembly may occasionally be under adverse weather conditions, or difficult working conditions, for example in suspension from a ladder, bucket arrangement or the like. Preferably the seal system is such that standard-sized, easy-to-manufacture, parts can be utilized, each part being individually customizable or tailorable (post-manufacture) to suit a particular cable arrangement. Also, preferably the seal system should be such as can be readily manufactured from not only conveniently handled and readily available materials, but also materials which can withstand adverse environmental conditions.
The above is only a limited discussion of the many features desirable in a sealant system for cable closures. It will be apparent from the following descriptions that problems to be addressed and preferably overcome by such a system are numerous.
An end closure system for a cable splice enclosures is disclosed in U.S. Pat. No. 4,262,168. The system disclosed therein comprises a split washer system. According to the system, a composite end seal or washer comprises two mating half-washers, each offset along a diameter and slit along an offset radius. As a result of the slit, which communicates between an edge the washer and central aperture, the washer can be placed over an already positioned cable. The system includes a plurality of concentric cut-out portions, to accommodate arrangements of various sizes. A cut-out portion or area is a section which can be cut open, by various means such as with shears or the like, for various reasons.
While the system of '168 is highly advantageous for many applications, it is not readily adaptable to systems involving a plurality of cables. Further, this system generally appears to require use of a mastic sealant, or tape, in association therewith, to achieve a good seal. Further, the system does not readily accommodate cable movement, non-coaxial alignment, or cable alignment not along a longitudinal axis of the closure.
A conical enclosure is disclosed in U.S. Pat. No. 4,468,620. A plurality of cables is accommodated, through the utilization of a plurality of cones. Each cone has a deformable, external, longitudinal rib, to provide snug engagement with a cable. While this arrangement also has its advantages, it does not appear to be convenient to assemble and, further, it is not apparent that it is appropriate for substantially universal application. That is, the cones apparently cannot be readily adapted to a wide variety of cable sizes, even though a small amount of adjustment can apparently be accommodated by the flexible longitudinal rib. Further, the arrangement does not appear particularly convenient to assemble and place in position.
U.S. Pat. Nos. 4,581,265 and 4,610,921 disclose wrap-around closure systems. The particular systems shown utilizes a fabric system that has conical ends tightly closed by means of: zippers; hook and loop closure systems; or the like.
Other splice closure systems are disclosed in U.S. Pat. Nos. 3,209,067; 3,816,642; and 4,079,193. All three illustrate attempts at addressing some of the above relating concerns.
None of the previously available arrangements for providing end seals have been satisfactory with respect to addressing the above related problems and concerns. What has been needed has been a convenient and satisfactory system.